The present invention relates generally to work vehicles, and more particularly to arrangements for providing auxiliary support systems in such work vehicles. More particularly, the invention relates to a flexible arrangement for providing one or more of electrical power, such as for welding, compressed air and hydraulic service in a stand-alone or integrated service pack in a work vehicle.
A wide range work vehicles have been developed and are presently in service. Present estimates are that hundreds of thousands of such vehicles are operative in the United States alone. Depending upon their intended use, work vehicles may include highly integrated systems for performing operations such as welding, cutting, assembly, and so forth. Moreover, vehicles have been developed for providing hydraulic and compressed air service to applications, such as for driving air tools, pneumatic lifts and other compressed air-driven devices, as well as hydraulic lifts, hydraulic tools, concrete and metal working tools, and so forth. Similarly, where electrical power is generated on a vehicle, this may be made available for powering electrical tools, lights, and a wide range of auxiliary devices.
Approaches to the design and operation of such work vehicles that incorporate auxiliary resources tend to take two separate paths. First, the auxiliary devices may be add-on systems that can simply be retrofitted to the vehicle. This is often the case for welding supplies and generators that are supplied in a stand-alone portable or semi-portable unit that can be mounted on or retrofitted to a vehicle, typically a truck. Attempts have been made to design such units for driving air compressors and hydraulic pumps as well, to provide pneumatic and hydraulic service.
In a second, quite different approach, the systems can be designed as original equipment in the vehicle, and driven directly by the vehicle engine or indirectly, such as by a belt, clutch or hydraulic motor receiving fluid from a pump that is driven by the vehicle engine. This is common in many applications where the auxiliary systems are provided as original equipment, either standard with the vehicle or as an option. In some of these arrangements, generators, pumps, air compressors, and so forth may be driven from a power take-off shaft which is, itself, driven by the main vehicle engine. A clutch or other selective engagement mechanism may be provided to enable the service systems to be driven when desired, and disengaged from the engine when the vehicle is transported to a work site.
While both of these approaches are effective and have their place in the market, they are not without drawbacks. For example, the stand-alone units occupy useful volume in the vehicles, typically in the bed of a truck. Moreover, they are subject to space and power constraints owing, in part, to the desire to maintain their volume relative small, and allow them to be kept portable. Such arrangements may be of limited accessibility to the user, such as for maintenance and servicing of the various components. Fully integrated systems driven by a vehicle engine, on the other hand, require that the vehicle engine be powered during periods of use of any one of the auxiliary systems. The vehicle engine is often grossly overrated as compared to the power needs of the auxiliary systems, and such operation reduces the overall life of the engine and drive train for vehicle transport needs. In many applications, the engine is left idling for extended periods between actual use of auxiliary systems, simply to maintain the option of using the systems without troubling the operator to start and stop the engine.
There is a need, therefore, for new approaches to the provision of auxiliary service, particularly electrical power, compressed air service and hydraulic service in work vehicles. There is a particular need for systems which avoid drawbacks of portable, retrofitted power supplies and service packs, while also avoiding the need to drive a main vehicle engine any time that auxiliary service is required.